Before you start down this path, you should be CERTAIN that the firmware has been corrupted, and that it is not some other problem. Sometimes the Galileo can seem unresponsive, and it is just a problem with the Windows COM driver.

The only way to be sure your firmware is corrupted is to plug in a serial cable and watch the messages from the BIOS. If you see a message that says "ASSERT_EFI_ERROR" then your firmware is corrupted, and flashing a new firmware (following the instructions below) will fix that problem.

NOTE: Changing the firmware in this method will cause your MAC address to be incorrect. This is only a problem if two Galileos have been fixed with this method, and then are attached to the same network.